1. Field of the Invention
The present invention relates generally to microrobots, and, more particularly, but not by way of limitation, to microrobots that are configured for micro- or nano-manipulation within a large actuation volume, and to methods, devices, and systems for such microrobots.
2. Description of Related Art
Robots have empowered manufacturing since the early 1960's when Unimation™ implemented a 1.5 m tall hydraulic manipulator to supply parts to die casting machines. Since then, robots have evolved with ever growing application areas such as industrial, medical, human-assistance, recreation, defense, etc. [1]. Over the past two decades, with the advent of microsystems and nanotechnology, precision requirements for robot manipulators have increased considerably, while robot sizes have generally decreased. Precision robots can be valuable tools for micro- and nano-manipulation [2], and for automated and teleoperated assembly [3-5]. More recently, micro- and nano-robots with sub-mm dimensions have been pursued [6-8].
Typical top-down micro- and nano-assembly hardware may use precision robots and end-effectors that are still many orders of magnitude larger than the size of the parts they manipulate [9]. With advances in Micro Electro Mechanical Systems (MEMS), new types of positioning stages have been proposed to aid nanoscale manipulation, probing and force measurement, optical microsystems, and high density data storage devices [10-11]. The design of such positioners often must balance key performance parameters such as range of motion, force output/payload capacity, and dexterity (degrees of freedom). A popular example of monolithically fabricated micropositioners is actuated using electrostatic comb-drives [11]. As a result, they have limited out-of-plane displacement outputs (e.g. mostly planar dexterity) [11]. Other examples include atomic force microscope (AFM) tips, which generally operate along a single vertical direction [12]. On the other hand, positioners with more than 3 degrees of freedom have been fabricated using thin-film deposition and etching, but they have limited force outputs, payload capacities, and reliability to operate as independent micromanipulators [13]. To overcome these inherent trade-offs, micro-positioners have been used as grippers or force probes in conjunction with larger conventional positioning stages, and therefore the overall dimensions of such manipulators typically spans several inches [14-15]. This is a severe limitation in applications requiring multiple such positioners within confined volumes, such as, for example, inside a scanning electron microscope (SEM) chamber.